1. Scientific Method - steps
1. State the problem
2. Form a hypothesis
3. Design an experiment
4. Evaluate the hypothesis
5. Repeat for accuracy

2. State the problem/Title
What do we want to know?
Can be a question
Form a hypothesis
Must be testable
Needs to make a prediction
Format “If ……. then…….
If – what is being tested – Independent variable
Then – predict what will happen – Dependent variable

3. Design an Experiment List of materials Safety precautions Variables
what you measure in an experiment
dependent variable
Data or results
What is being measured
Y-axis
independent variable
“If”; “I” change
What is being manipulated by the experimenter
X-axis

4. Design an Experiment Step by step procedure 2 groups –
Experimental group – gets the Independent variable (ONLY 1!!!) – the factor being tested – “I” change or manipulate
Control group - for comparison – does NOT get the independent variable – gets a placebo
Constants – NOT the control – things to be kept the same between all the groups
Data table – to record results/data – the Dependent variable – 2 types
Quantitative – can be measured
Qualitative – is descriptive

5. Design an Experiment Organize your data Analyze your data
Allows you to see trends and patterns more easily (graphs)
Analyze your data
Does the data have meaning?
Is there a significant difference in the results between the control and the experimental group?
Sources of error – NOT mistakes
Factors you couldn’t or didn’t control for

6. How’s a critter to choose?
Graphs
line graphs
graphing data that shows
continuous change
bar graphs (or histograms)
graphing data that is in disconnected groups
How’s a critter to choose?

7. elevation (feet above sea level)
How does elevation affect temperature?
Line graph!
elevation (feet above sea level)
temp.
(°C) 30
500 25
1000 20
1500 15
2000 10
2500 5 30 25 20 18
temperature 15 10
1200 ft? 5
500
1000
1200
1500
2000
2500
elevation

8. Which drink do you like best?
number
Coke 1
Pepsi
Water 4
Iced tea
Gatorade 3 6
Bar graph! 5 4
number of students 3
Red Bull? 2 1
Coke RB
Pepsi RB
water
tea
Gatorade
type of drink 8

9. Evaluate the Results - Conclusion
Data does NOT support hypothesis – there was no significant difference OR you got unexpected results →
Doesn’t mean you did it wrong
Revise hypothesis and experiment as necessary and try again

10. Evaluate the Results - Conclusion
Data supports hypothesis – you got the results you expected →
Repeat, Repeat, Repeat!!!
If of scientific value – publish so others can repeat, repeat, repeat
If supported again and again → THEORY
FACTS can be proven
LAWS are known to be true, but may not be explainable (ex – gravity)

11. Examples of experiments 1
How does fertilizer affect the growth rate of plants?
we set up an experiment testing different amounts of fertilizer on different plants & measuring the growth (height) of the plants:
dependent variable (Y-axis)?
height of plants
independent variable (X-axis)?
amount of fertilizer
The effect of _____________ on _____________
Amount of Fertilizer
Height of Plants